Author: Robert Reuter, Mark WorstellPublication: Sandia National LaboratoriesYear Published: 1978 Torque ripple is a name given to time variations in torque which are propagated through the drive train of wind energy conversion systems.This paper covers an analytical and experimental investigation of torque ripple in a Darrieus vertical axis wind turbine. An analytical model of the…
Author: Curtis DoddPublication: Sandia National LaboratoriesYear Published: 1977 This report contains the results of lightning protection studies for Vertical Axis Wind Turbines. The methodology is established for determining the chances for a lightning strike at a VAWT site. Proposed designs include an insulator design, a brush by-pass design, a cone of protection, lightning elimination device,…
Author: Elie Bou-Zeid and Alexander SmitsPublication: Princeton Environmental InstituteYear Published: 2013 Vertical axis wind turbines (VAWTs) are proposed as an alternative to the more commonly used horizontal axis wind turbines (HAWTs) due to the potential increase in packing density (reduction in distance between turbines) that is possible with VAWTs. But for VAWTs to be more…
Author: M.A. Miller, S. Duvviri, Ian Brownstein, John Dabiri, M. HultmarkPublication: J. Fluid DynamicsYear Published: 2018 Laboratory experiments were performed on a geometrically scaled vertical-axis wind turbine model over an unprecedented range of Reynolds numbers, including and exceeding those of the full-scale turbine. The study was performed in the high-pressure environment of the Princeton High…
Author: Sam Kanner, Per-Olof PerssonPublication: University of California BerkeleyYear Published: 2018 A high-order Wall-Resolved Implicit Large Eddy Simulation (WR-ILES) method is used to simulate a vertical-axis wind turbine in 2D and 3D. In this work, we perform these simulations at nearly full-scale Reynolds numbers (O(105)). The high-order simulations are compared to experimental wind tunnel data,…
Author: Tristen Charles HohmanPublication: Princeton UniversityYear Published: 2017 The performance and wake structure of a model vertical axis wind turbine (VAWT)is studied, subject to various blade geometries, modes of operation, and inflow conditions. To facilitate this investigation, the neutral atmospheric boundary layer (ABL) must be simulated in a short recirculating wind tunnel. This is achieved…
Author: Sam Kanner, Per-Olof PerssonPublication: Energy Conversion and ManagementYear Published: 2018 The accuracy of CFD simulations of vertical axis wind turbines (VAWTs) is known to be significantly associated with the computational parameters, such as azimuthal increment, domain size and number of turbine revolutions before reaching a statistically steady state condition (convergence). A detailed review of…
Author: L. LazauskasPublication: Wind EngineeringYear Published: 1992 The desirable performance attributes of a vertical axis wind turbine (VAWT) include high starting torque, high peak efficiency, broad operating range and a reasonable insensitivity to the parameters that define its operation. The theoretical performances of three variable pitch mechanisms for VAWT are compared. Cycloturbines use cam devices…
Author: Baolin Li, Zhixin Bian, Kedi ChenPublication: Boletín TécnicoYear Published: 2017 The performance of wind turbines is usually evaluated by proprietary parameters, but these parameters are used to analyze the dynamic performances of the blades qualitatively. Thus,it cannot exactly express the actual working performances of wind turbines. In this paper, a comparative analysis on physical…
Author: David MalcolmPublication: Wind EnergyYear Published: 2019 Vertical axis wind turbines have suffered from the periodic nature of the aerodynamic loads and early efforts at commercialization were plagued by fatigue issues resulting from an inability to anticipate critical resonances. This paper examines the criteria for determining whether intersections of harmonics of the rotor speeds and…